Sampling hydrocarbon fluids from subterranean formations involves positioning a downhole tool in a borehole adjacent a formation, sealing an interval of the borehole along the tool and adjacent the formation and extracting sample fluid from the formation. The sample fluid may then be evaluated (e.g., downhole and/or at the surface of the Earth) to facilitate drilling and/or hydrocarbon production operations.
Prior to collecting a fluid sample for evaluation, the sealed borehole interval is subjected to a cleanup operation during which contaminates such as wellbore fluid (e.g., drilling fluid), filtrate and the like are substantially removed to enable the collection of a substantially uncontaminated formation fluid sample. Some known downhole sampling tools include multiple sampling ports located between packers so that a location within a sampling interval for which cleanup and sampling are performed may be adjusted by selecting a different one of the ports. For example, each of the ports may have a corresponding valve to enable fluid to be drawn from a selected one of the ports. In this manner, the properties of the fluid obtained by each of the ports can be evaluated and one or more of the ports providing the highest quality sample fluid can be selected to collect a sample for further evaluation. Other known downhole sampling tools enable movement of a sampling port within a sample interval to achieve similar results.
However, the above-mentioned known downhole sampling tools include a relatively complex arrangement of valves and flowlines within the sample interval to enable adjustment of the fluid collection port. Such complex valve and flowline arrangements are both costly and create potential failure points within the sample interval.